Active ingredient components useful as a pesticide, such as insecticides and fungicides, have been prepared into a formulation, such as emulsifiable concentrate, emulsion, wettable powder, suspension and water dispersible granule, depending upon their physicochemical properties and the objective to use them practically in agricultural crop fields. In order to supplement the deterioration of long-lasting activity of pesticidal components, which might be caused by any reason such as dilution of the pesticidal components on the surface of plant leaves due to the growth of the leaves themselves, photodegradation of the pesticidal components on the surface of leaves, and carrying away of pesticidal components from the surface of leaves due to rainfalls, etc., and exceeding degree of pesticide application has been performed onto agricultural crops for minimizing their damages caused by pest insects and plant diseases and for keeping the quality of cultivated crops. However, such exceeding degree of pesticide application has imposed a burden not only in terms of laboring and economical point of view but also caused environmental pollution.
Therefore, various efforts to find out the means to reduce the amount of pesticides used in the environment have been made. As a method to prevent the deterioration in efficacy of a pesticide due to rainfalls, a method to prepare a pesticide composition for coating use having good raindrop resistance by containing .alpha.-starch therein is disclosed in Japanese Patent Laid-open No. Sho 54-80423 Gazette, and a wettable powder formulation of which raindrop resistance being improved by an incorporation of a resin in powder therein is disclosed in Japanese Patent Laid-open No. Sho 59-172401 Gazette, and a water dispersible granule with improved-raindrop resistance prepared by incorporating polyvinyl alcohol, carboxymethylcellulose, etc. therein to enhance sticking property is disclosed in Japanese Patent Laid-open No. Hei 2-40301 Gazette, for example.
Whereas, in Japanese Patent Laid-open No. Hei 1-190610 Gazette, a pesticide composition containing 1-10% by weight of sorbitan trioleate is disclosed. However, no description has been made yet on a pesticide composition which contains high content of sorbitan trioleate as much as 10-50% by weight for aiming at improving its raindrop resistance.